EP1437102A1

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Info

Publication number: EP1437102A1
Application number: EP04006096A
Authority: EP
Inventors: Kazuo C/O Fuji Photo Film Co. Ltd. Shimura; Takeshi c/o Fuji Photo Film Co. Ltd. Ohkubo
Original assignee: Fuji Photo Film Co Ltd
Current assignee: Fujifilm Holdings Corp
Priority date: 2000-09-18
Filing date: 2001-09-17
Publication date: 2004-07-14
Anticipated expiration: 2021-09-17
Also published as: DE60115722T2; EP1188421A3; EP1437102B1; EP1188421A2; DE60109541T2; EP1428486A1; US6692448B2; DE60109541D1; US20020055692A1; DE60115722D1; DE60116804D1; DE60116804T2; US7039225B2; EP1428486B1; US20030181831A1; EP1188421B1

Abstract

An artificial bone template selection system includes atemplate data storage system in which template data representinga plurality of templates representing a plurality of artificialbones of different shapes is stored. A bone shape measuringsystem measures the shape of bone to be replaced by artificialbone on the basis of bone image data representing an imageincluding the bone to be replaced by artificial bone. Aprospective template selection system selects at least onetemplate the shape of which substantially conforms to the shapeof the bone to be replaced by artificial bone as measured bythe bone shape measuring system out of the plurality of templatesrepresented by the template data.

Description

BACKGROUND OF THE INVENTIONField of the Invention

Description of the Related Art

In the orthopedic surgery, the oral surgery and the like,when a patient loses a part of a bone due to disease or accidentor by a surgical removal as treatment for malignant tumor, thelost part of the bone has been replaced by his or her own boneof another part.

Recently, artificial bone (artificial hard tissue) ofstainless steel, cobalt-chrome series alloy, metal such astitanium, aluminum or zirconium, oxide of these metals, ceramicsuch as apatite, or composite material of these materials has been put into practical use as substitution for the lost partof the bone.

Artificial bone which is to be embedded in place of thelost part of the bone is produced on the basis of a standardmodel which is selected, on the basis of the shape of the partto be replaced by the artificial bone, out of a plurality ofstandard models which have been prepared, in advance, indifferent shapes.

Conventionally, the standard models are stored in the formof real templates representing the contours of the standardmodels(e.g., templates formed of transparent plastic sheets),and the real templates are superposed on an image of the lostpart of the bone in sequence and whether each of the templatesconforms to the lost part of the bone is visually checked.

However, since the standard models are prepared atintervals of 1mm of the diameter of the bone head (the head ofthe bone) or the length of the bone shaft or the bone holderand at intervals of 1° of the angle between the bone shaft andthe bone holder, the number of the standard models or the realtemplates is numerous, and accordingly, to select one templatein the conventional way is a time-consuming and labor-consumingprocess.

Further, since being manually superposed on the image ofthe lost part of the bone in a limited time interval, eachtemplate cannot be accurately aligned with the image of the lostpart and an optimal standard model or template cannot be constantly selected.

Further, since numerous templates must be kept at hand,management of the templates is troublesome.

SUMMARY OF THE INVENTION

In view of the foregoing observations and description, theprimary object of the present invention is to provide anartificial bone template selection system which can efficientlyselect an artificial bone template suitable for the part of boneto be replaced by artificial bone out of a plurality of artificialbone templates prepared in advance.

Another object of the present invention is to provide anartificial bone template display system which displaysartificial bone templates in such a manner that a suitabletemplate can be selected in a shorter time, and management oftemplates can be facilitated.

Still another object of the present invention is to providea template data storage system which stores electronic data onthe templates in such a manner that a suitable template can beselected in a shorter time.

Still another object of the present invention is to providea computer-readable recording medium which stores electronicdata on the templates in such a manner that a suitable templatecan be selected in a shorter time.

In accordance with a first aspect of the present invention,there is provided an artificial bone template selection systemcomprising a template data storage means in which template data representing a plurality of templates representing a pluralityof artificial bones of different shapes is stored, a bone shapemeasuring means which measures the shape of bone to be replacedby artificial bone on the basis of bone image data representingan image including the bone to be replaced by artificial bone,and a prospective template selection means which selects, asa prospective template, at least one template the shape of whichsubstantially conforms to the shape of the bone to be replacedby artificial bone as measured by the bone shape measuring meansout of the plurality of templates represented by the templatedata.

Preferably, there are provided a display means whichdisplays the bone image representing the shape of the bone tobe replaced by the artificial bone and an image of the prospectivetemplate (s) selected by the prospective template selection meansand a display control means which causes the display means todisplay the bone image and the image of the prospective templatesuperposed one on another.

In accordance with a second aspect of the present invention,there is provided an artificial bone template selection systemcomprising a template data storage means in which template datarepresenting a plurality of templates representing a pluralityof artificial bones of different shapes is stored, a bone imagedisplay means which displays the bone image representing theshape of the bone to be replaced by the artificial bone, a featurepoint designating means which designates on the bone image displayed by the bone image display means a feature pointrepresenting the shape of the bone, a bone shape specifying meanswhich specifies the shape of the bone on the basis of the featurepoint designated by the feature point designating means, anda prospective template selection means which selects, as aprospective template, at least one template the shape of whichsubstantially conforms to the shape of the bone specified bythe bone shape specifying means out of the plurality of templatesrepresented by the template data.

The artificial bone template selection system inaccordance with the second aspect of the present inventiondiffers from that of the first aspect of the present inventionin that the former specifies the shape of the bone to be replacedby the artificial bone on the basis of a feature point designatedon the image of the bone displayed by the display means whereasthe latter specifies the shape of the bone to be replaced bythe artificial bone on the basis of the bone image data.

As the feature point representing the shape of the bone,the center of the bone head, the edge of the bone head, thelongitudinal ends of the bone shaft and the bone holder, andthe like may be used. By designating the center and the edgeof the bone head, the diameter of the bone head can be specified,and by designating the longitudinal ends of the bone shaft andthe bone holder, the lengths of the bone shaft and the bone holderand the angle therebetween can be specified. Further, when thediameter of the bone head, the lengths of the bone shaft and the bone holder and the angle therebetween are specified, theoverall shape of the bone can be specified.

Preferably there are provided a display means whichdisplays an image of the prospective template(s) selected bythe prospective template selection means and a display controlmeans which causes the display means to display the bone imageand the image of the prospective template superposed one onanother.

When the bone image and the image of the prospectivetemplate are displayed superposed one on another in theartificial bone template selection system in accordance withthe first or second aspect of the present invention, it ispreferred that an image processing means which carries out imageprocessing on at least one of the images displayed by the displaymeans so that their shapes can be more clearly discriminatedbe provided, and the image processed by the image processingmeans is displayed in the processed condition.

The expression "so that their shapes can be more clearlydiscriminated" means "so that discrimination between the shapesof the prospective templates is facilitated" (in the case wherea plurality of prospective templates are selected) as well "sothat discrimination between the shapes of the prospectivetemplate and the bone image is facilitated".

In the artificial bone template selection system inaccordance with the first or second aspect of the presentinvention, it is preferred that an order information output means which outputs, for instance, a data file on information forordering artificial bone corresponding to the template selectedby the prospective template selection means, e.g., maker, modelnumber, number, delivery time, place of delivery, and the like,be provided.

The information for ordering the artificial bone need notbe for all the prospective templates selected by the prospectivetemplate selection means but may be for only a final templatewhich is finally selected from the prospective templatesselected by the prospective template selection means.

The template data used in the artificial bone templateselection system in accordance with the first or second aspectof the present invention is preferably prepared not only forstoring images of the templates as electronic data but also forfacilitating retrieval and shape matching. For example, thetemplate data preferably comprises an image file in which aplurality of pieces of image data each representing one templateare recorded and a shape data file in which a plurality of piecesof shape data (e.g., vector data) each representing a featureof the shape of a template are recorded in correlation with theimage data for the template.

The template data comprising the image data and the shapedata may be provided recorded on a computer-readable recordingmedium.

In the artificial bone template selection system inaccordance with the first aspect of the present invention, one or more prospective templates, the shape of which substantiallyconforms to the shape of the bone to be replaced, can beautomatically selected without visually checking whether eachof the templates conforms to the bone or manually superposingeach of the templates on the image of bone, whereby one or morestandard artificial bone can be selected easily in a short time.

Further, when the bone image and the image of theprospective template are displayed superposed one on another,whether the prospective template is really suitable for the boneto be replaced can be judged observing the superposed image.In this case, since the number of the prospective templates islimited by the automatic selection, a template most optimal tothe bone can be easily and quickly selected.

In the artificial bone template selection system inaccordance with the second aspect of the present invention, oneor more prospective templates, the shape of which substantiallyconforms to the shape of the bone to be replaced, can beautomatically selected even if the bone is too complicated inshape for the artificial bone template selection system inaccordance with the first aspect of the present invention toselect a template suitable for the bone.

As in the artificial bone selection system in accordancewith the first aspect of the present invention, when the boneimage and the image of the prospective template are displayedsuperposed one on another, whether the prospective template isreally suitable for the bone to be replaced can be judged observing the superposed image. In this case, since the numberof the prospective templates is limited by the automaticselection, a template most optimal to the bone can be easilyand quickly selected.

Further, in both the artificial bone template selectionsystems in accordance with the first and second aspects of thepresent invention, since a template data storage means in whichtemplate data representing a plurality of templates representinga plurality of artificial bones of different shapes is storedin the form of electronic data is used, management of thetemplates becomes unnecessary.

Further, in both the artificial bone template selectionsystems in accordance with the first and second aspects of thepresent invention, when an image processing means which carriesout image processing on at least one of the images displayedby the display means so that their shapes can be more clearlydiscriminated is provided and the image processed by the imageprocessing means is displayed in the processed condition, thebone image and the image of the prospective template can be easilydiscriminated from each other, which permits the operator tomore accurately locate the images with respect to each otherin a short time. Further, a template most optimal to the bonecan be easily and quickly selected, and at the same time, relativeposition between the images can be more finely adjusted, wherebymost optimal template can be surely selected.

Further, when the artificial bone template system is provided with an order information output means which outputs,information for ordering artificial bone corresponding to thetemplate selected by the prospective template selection means,an automatic artificial bone order system which automaticallyorders artificial bone as soon as the prospective templateselection processing can be realized. When the system isincorporated in a network such as using the internet, the usersuch as a doctor, a medical engineer and the like can directlytrade with a maker or an agency without intervening therebetweena broker.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a block diagram showing an artificial bonetemplate selection system in accordance with a first embodimentof the present invention,

Figure 2 is a schematic view showing an appearance of theartificial bone template selection system shown in Figure 1,

Figure 3 is an enlarged view of a part including a femuras a bone to be replaced,

Figure 4 is a view showing an example of the frame on thebasis of which the template selection processing is carried out,

Figure 5 is a block diagram showing an artificial bonetemplate selection system in accordance with a second embodimentof the present invention,

Figure 6 is a view for illustrating a method of designatingon the displayed bone image a feature point representing theshape of the bone,

Figure 7 is a block diagram showing in detail the templatedata storage means,

Figure 8 is a view showing an example of the structure oftemplate data, and

Figures 9A and 9B are views showing another example of thestructure of template data.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In Figure 1, an artificial bonetemplate selection system1 in accordance with a first embodiment of the present inventioncomprises a template data storage means 10 in which templatedata representing a plurality of templates representing aplurality of artificial bones of different shapes is stored,a bone shape measuring means 20 which measures the shape of boneto be replaced by artificial bone on the basis of bone imagedata S1 representing an image including the bone to be replacedby artificial bone, a prospective template selection means 30which selects, as a prospective template, at least one templatethe shape of which substantially conforms to the shape of thebone to be replaced by artificial bone as measured by the boneshape measuring means 20 out of the plurality of templatesrepresented by the template data, a display means 40 0 (e.g., aCRT or a liquid crystal panel) which displays the bone imagerepresenting the shape of the bone to be replaced by theartificial bone and an image of the prospective template(s)selected by the prospective template selection means 30, an imageprocessing means 50 which carries out image processing on the images displayed by the display means so that their shapes canbe more clearly discriminated from each other, a display controlmeans 60 which causes the display means 40 to display the boneimage and the image of the prospective template superposed oneon another on the basis of the processed image data, and an orderinformation output means 70 which outputs order information forordering artificial bone for replacing the bone.

The artificial bonetemplate selection system 1 furthercomprises ashaping means 80 which deforms, on the screen ofthe display means 40, the shape of a standard templaterepresented by template data read out from the template datastorage means 10, a storage means 81 which stores differencedata D3 representing the difference in shape between the standardtemplate and a deformed template obtained by deforming thestandard template by the shaping means 80, and an input means90 (consisting of akeyboard 91, adial 92, amouse 93 and thelike) for inputting data for selecting a more desirable templateout of prospective templates and/or for carrying out variousoperations.

As shown in Figure 2, the display means 40, the input means90 and the like are placed on a table 2, and the template datastorage means 10, the bone shape measuring means 20 and the likeare contained in abody 3 under the table 2.

The template data storage means 10 comprises, for instance,a magnetic recording device such as a hard disc which reads outtemplate data from a computer-readable portable recording medium such as a CD-ROM or a MO and temporarily stores the templatedata read out. When the speed of the selection (retrieval) tobe described later does not involve a problem, the template datamay be read out from the computer-readable portable recordingmedium such as a CD-ROM or a MO on the spot.

The template data comprises an image file in which aplurality of pieces of image data each representing one templateare recorded and a shape data file in which a plurality of piecesof template shape data D1 each representing a feature of theshape of a template are recorded in correlation with the imagedata for the template. The image file includes, in addition tolife-size images of the standard templates, thumbnail images(scale-down images) of the standard templates (e.g., reduced1/8 by 1/8).

By storing template images in the form of electronic data,whether each template conforms in shape to the bone to be replacedcan be checked on the basis of electronic data and the necessityof keeping numerous templates at hand and managing the templatescan be eliminated.

In this particular embodiment, vector data representinga geometrical feature is employed as the shape data D1. In thecase of a femur, the diameter of the bone head, the length ofthe bone shaft, the length of the bone holder between the bonehead and the bone shaft and/ or the angle between the bone shaftand the bone holder can be employed as the vector data. Withthis arrangement, a database for facilitating retrieval and shape matching can be obtained.

The bone shape measuring means 20 comprises ameasuringsection 21 which measures the shape of the bone to be replacedon the basis of the image data S1, and astorage section 22 whichstores bone shape data D2 representing the shape of the bonemeasured by themeasuring section 21.

The prospective template selection means 30 carries outselection (retrieval) for selecting a standard template, whichconforms to the shape of the bone to be replaced, on the basisof the bone shape data D2 obtained by measuring the bone (readout from the storage section 22) and the template shape dataD1 read out from the template data storage means 10.

The image processing means 50 carries out image processingfor facilitating discrimination between the shape of thetemplate and the shape of the bone. For example, the imageprocessing means 50 carries out image processing, during or afterselection of the standard template, for displaying the edge ofthe bone and/or the template only in line, shading the image,displaying contour lines, displaying the overall shapes the boneand/or the template in a wire frame fashion or enhancing theedge of one of the bone and the template.

The display control means 60 sets layout of the frame ofthe display means 40 so that a template display area, where alist of prospective templates automatically selected by theprospective template selection means 30 and/or thumbnail imagesof the prospective templates is displayed and a bone image display area, where an image of the bone is displayed, areprovided side by side. Further, the display control means 60causes the display means 40 to display the image of the boneand the image of the template ( the processed image, when ithas been processed by the image processing means 50) in thetemplate display area superposed one on another.

In the superposed display, all the prospective templatesmay be automatically located to be superposed on the image ofthe bone or only one or more of the prospective templates selectedby the operator out of the prospective templates automaticallyselected by the prospective template selection means 30 may besuperposed on the image of the bone. In the latter case, theprospective template(s) may be located under the instructionof the operator.

By thus setting the template display area and the boneimage display area, the image of the bone and the list of theprospective templates (with the thumbnail images of theprospective templates) can be displayed simultaneously, and afinal most optimal template can be selected at high efficiencyout of a plurality of prospective templates automaticallyselected by the prospective template selection means 30.

Operation of the artificial bonetemplate selection system1 of this embodiment will be described, hereinbelow.

It is consumed here that a femur 9 (Figure 3) is to bereplaced by artificial bone, and a radiation image (CR image)including the image of thefemur 9 is taken by a CR (computed radiography) system. That is, X-rays are projected through anobject onto an imaging plate comprising stimulable phosphor sothat a radiation image of the object is recorded on the imagingplate as a pattern of stored radiation energy. Then theradiation image recorded on the imaging plate is read out andbone image data S1 is obtained. The bone image data S1 is inputinto the artificial bonetemplate selection system 1 of thisembodiment.

The display control means 60 causes the display means 40to display afemur 9 with alost part 9a together with

bones

7 and 8 around thefemur 9 in the bone image display area onthe basis of the bone image data S1 as shown in Figure 4.

The bone image data S1 is input also into the measuringsection 21 of the boneimage measuring system 21. The measuringsection 21 extracts the edge of thefemur 9 with the lostpart9a by a known method and stores bone shape data representingthe outer shape of thefemur 9 in thestorage section 22. Thebone shape data D2 is in the same format as the template shapedata D1 stored in the template data storage means 10. In thisparticular embodiment, since the template shape data D1 is vectordata, the measuringsection 21 obtains vector data representingthe diameter of thebone head 9b, the length of thebone shaft9c, the length thebone holder 9d and/or the angle between thebone shaft 9c and thebone holder 9d and stores the vector datain thestorage section 22 as the bone shape data D2.

The information specifying thebone 9 with the lostpart 9a to be replaced by artificial bone may be extracted from amenu code attached to the bone image data S1 or may be specifiedby the operator designating a point with themouse 93 on theframe of the display means 40.

Thereafter, the prospective template selection means 30reads the template shape data D1 of templates for a femur fromthe template data storage means 10, and selects one or moretemplates whose outer shape conforms to the contour of thefemur9 of the patient on the basis of the bone image data S1. Theselection may be based on a pattern matching between the twopieces of image data in a raster form. However, it is preferredthat the selection be carried out on the basis of comparisonbetween the template shape data D1 and the bone shape data D2.That is, since the template shape data D1 and the bone shapedata D2 are both vector data representing the diameter of thebone head 9b, the length of thebone shaft 9c, the length thebone holder 9d and/or the angle between thebone shaft 9c andthebone holder 9d, the selection (retrieval) can be done ina shorter time as compared with when the selection is done bysimple pattern matching on the raster data.

The prospective template selection means 30 determineswhether each of the standard templates for a femur conforms tothefemur 9 with the lostpart 9a, and automatically selectsone or more of the standard templates whose difference from theaffected femur 9 is within a predetermined range. When thereis no standard template whose difference from theaffected femur 9 is within the predetermined range, the prospective templateselection means 30 selects one or more of the standard templatesclose to the predetermined range. In this manner, theprospective template selection means 30 selects at least onestandard template as a prospective template.

The prospective template selection means 30 inputs intothe display control means 60 information J1 on the prospectivetemplate(s) selected. The display control means 60 causes thedisplay means 40 to display the numbers of the prospectivetemplates selected (e.g., template A to template D) togetherwith the thumbnail images thereof in the template image displayarea. It is preferred that the thumbnail images be read out fromthe template data storage means 10. When the thumbnail imagesare not prepared in advance, they are obtained by reducing theoriginal image.

In addition to the numbers and the thumbnail images of theprospective templates, information on the maker, model numberand the like of the artificial bone represented by theprospective templates may be read out from the template datastorage means 10 and displayed in the template display area.

Further, the list of the prospective templates (e.g., thenumber of the prospective templates, the model number of thesame, and the like) may be output on a recording medium suchas paper as well being displayed by the display means 40.

The operator or the doctor determines whether theautomatic selection is satisfactory on the basis of the list and/or the thumbnail images of the selected prospectivetemplates. When the automatic selection is satisfactory, theoperator inputs the effect that the automatic selection issatisfactory into the artificial bonetemplate selection system1.

It is possible to check whether the automatic selectionis satisfactory by superposing the prospective templates(limited in number) on the CR film image of the affectedbone9. Also in this case, since the number of the prospectivetemplates has been reduced by the automatic selection, thechecking can be done in a shorter time.

When it is determined that the automatic selection isunsatisfactory or when it is required to further reduce thenumber of the prospective templates (e.g., to 1), the bone imagedata S1 is analyzed in further detail, and templates whichfurther conform to the bone in shape are selected out of theprospective templates. This selection may be done in thefollowing manner by operating thekeyboard 91, themouse 93,thedial 92 and the like viewing the screen of the display means40.

That is, the display means 40 is caused to display atemplate selection frame such as shown in Figure 4. Then, theoperator selects one of the templates in the list of prospectivetemplates (or the thumbnail images thereof) displayed in thetemplate display area on the screen of the display means 40.This selection may be done by pointing with themouse 93 the template to be selected or by inputting the number of the templateto be selected through thekeyboard 91.

When one of the prospective templates is selected, theprospective template selection means 30 reads out image datarepresenting the selected prospective template in an originalsize from the template data storage means 10 and inputs it intothe image processing means 50. Then the display control means60 causes the display means 40 to display an image of the selectedprospective template in the original size.

Thereafter, the image of the selected prospective imagein the original size is moved to the image of thebone 9 to bereplaced by artificial bone and superposed thereon. Thisoperation of superposing the image of the selected prospectiveimage in the original size on the image of thebone 9 to be replacedis preferably done by drag and drop with themouse 93.

At this time, it is preferred that image processing means50 carries out image processing for facilitating discriminationbetween the shape of the prospective template and the shape ofthe bone. For example, the image processing means 50 carriesout image processing for enhancing edges of the images, shadingthe one of the images, displaying the edge of the bone and/orthe template only in line (solid line or dotted line), displayingthe overall shapes the bone and/or the template in a wire framefashion or displaying the images in different colors. Ifrequired, the images may be displayed in an enlarged size sothat whether the selected prospective template well conforms to the bone to be replaced can be visually checked more easilyand superposing accuracy is increased.

The image of the selected prospective template moved tothe image of the bone is finely moved up and down and right andleft and finely rotated so that the image of the selectedprospective template conforms to the image of the bone to bereplaced in position, inclination and the like. These operationis preferably carried out by designating a translating movementmode or a rotational movement mode by thekeyboard 91 and movingthe image of the selected prospective template by a distanceor an angle corresponding to the amount of rotation of thedial92.

This process is repeated while changing the prospectivetemplates and selecting a prospective template most suitablefor thebone 9 to be replaced. In this manner, information ona final prospective template is stored in the storage means 81.

When thebone 9 is not to be replaced in whole but artificialbone is embedded only in place of the lostpart 9a of thefemur9, geometrical data such as coordinates of theedge 9f (Figure3) of the lostpart 9a of thefemur 9 for defining thelost part9a on the prospective templates is also stored in the storagemeans 81.

If desired, the template shape data D1 on the finalprospective template is input into the shaping means 80 and theprospective template is slightly enlarged or reduced in wholeor a part of the template is finely deformed so that the final prospective template is adjusted to a shape which strictlyconforms to the shape of thebone 9 to be replaced. Thendifference data D3 representing the difference of the shape ofthe final prospective template after the adjustment from thatbefore the adjustment is stored in the storage means 80.

The fine deformation of only a part of the finalprospective template is preferably carried out by firstdesignating the part to be deformed with themouse 93,designating a translating movement mode or a rotational movementmode by thekeyboard 91 and then deforming the designated partby a value corresponding to the amount of rotation of thedial92. Such a local deformation can be carried out by changingcoordinate parameters and/or function parameters which definethe shape of the template and are obtained on the basis of thetemplate shape data D1.

The amount of movement of the image of the template or theamount of change of the parameters when the image of the templateis to be moved or the template is to be partly deformed can beset also by inputting numerical values through thekeyboard 91.

The operation of deforming the template or moving the imageof the template can be easily carried out when the image of thebone to be replaced and the image of the template are displayedsuperposed one on another. Further since such operation iscarried out only on templates which have been automaticallyselected on the basis of the image data, selection of a suitabletemplate can be carried out in a shorter time.

Then an order file for ordering artificial bonecorresponding to the template thus selected, e.g., maker modelnumber (template number), number of the templates, delivery time,place of delivery, the difference data D3, and the like, is madeby the order information output means 70 and the order file issent to a maker or an agency.

An artificial bone template selection system in accordancewith a second embodiment of the present invention will bedescribed with reference to Figures 5 and 6, hereinbelow.

In the artificial bone template selection system inaccordance with the second embodiment of the present invention,feature points are designated on the image of the bone to bereplaced and the bone shape data D2 representing the shape ofthe bone to be replaced is obtained on the basis of the designatedfeature points.

In this embodiment, as the means for designating thefeature points on the image displayed by the display means 40,a pointing device such as amouse 93 is employed, and a boneshape specifying means 26, which obtains as vector data the boneshape data D2 on the basis of the designated feature points,is provided in place of the bone shape measuring means 20 employedin the first embodiment.

In the artificial bonetemplate selection system 1 of thesecond embodiment, the operator designates feature points onthe image of the bone displayed by the display means 40. Thisdesignation may be carried out, for instance, by designating the diameter of thebone head 9b by pointing the center 9g andtheedge 9h of thebone head 9b, designating the length of thebone shaft 9c by pointing the longitudinal ends 9m and 9n,designating the length of thebone holder 9d by pointing thelongitudinal ends 9j and 9k and designating the angle  betweenthebone shaft 9c and thebone holder 9d by pointing thelongitudinal ends 9m and 9n of thebone shaft 9c and thelongitudinal ends 9j and 9k of thebone holder 9d. The boneshapespecifying means 26 obtains as vector data the bone shape dataD2 on the basis of the designated feature points. Theprospective template selection means 30 selects at least oneof the standard templates as a prospective template in the samemanner as that employed in the first embodiment.

Since pointing the feature points with themouse 93 canbe intuitively done observing the image of the bone displayedon the display means 40, the shape of the bone can be suitablyspecified even if the bone is complicated in shape and selectionof the artificial bone template can be automatically carriedout.

Though preferred embodiments of the present invention aredescribed above, the present invention need not be limited tothe embodiments described.

For example, though, in the embodiments described above,the bone shape data D2 is obtained as vector data and whetherthe template conforms in shape to the bone to be replaced ischecked by the use of the bone shape data D2 in the form of vector data and the template shape data D1 also in the form of vectordata, whether the template conforms in shape to the bone to bereplaced is checked by pattern matching by the use of rasterdata representing the bone to be replaced and raster datarepresenting the standard template.

Further, after prospective templates are automaticallyselected by the prospective template selection means 30, imagesof all the prospective templates may be superposed on the imageof the bone to be replaced by automatic alignment processingand which of the prospective templates is the best may bedetermined viewing the superposed image.

In this case, when the prospective template selectionmeans 30 selects a plurality of prospective templates, it ispreferred that the contours of the image of the bone and theprospective templates be displayed in a wire frame fashion andthe wire frames for the respective image be displayed indifferent colors.

Further, when the prospective template selection means 30selects a plurality of prospective templates, it is possibleto set a display area for each prospective template and displaya superposed image in each display area.

Prospective templates can be clearly discriminated fromeach other by the use of such a layout.

As the image data S1 representing an image including thebone to be replaced by artificial bone, image data obtained byreading out an image on X-ray film by an image scanner, cross-sectional image data obtained by CT or MRI,three-dimensional image data obtained by reconfiguration, orthe like may be employed in place of a radiation image read bya CR system.

The template data storage means 10 will be described inmore detail with reference to Figures 7 to 9B, hereinbelow.

As shown in Figure 7, the template data storage means 10comprises arecording section 11 which records data on apredetermined recording medium and arecording section 15 whichreads out data from the recording medium. Therecording section11 comprises an image file recording means 12 which records aplurality of pieces of template image data D4, each piecerepresenting an image of one template, in an image file, a shapedata extracting means 13 which extracts a plurality of piecesof template shape data D1, each representing a feature of theshape of a template, on the basis of template image data D4 oneach template, and a shape file recording means 14 in which thepieces of template shape data D1 extracted by the shapedataextracting means 13 are recorded in correlation with the templateimage data for each template.

The recording medium employed in therecording section 11or thereading section 15 may be a computer-readable portablerecording medium such as a CD-ROM, CD-RAM, DVD-ROM, DVD-RAM.ora MO as well as a fixed type magnetic recording medium such asa hard disc.

Thereading section 15 is provided with a recording/reading means 16 which reads out template datarecorded on a portable recording medium such as a CD-ROM, MOor the like and temporarily. stores the template shape data readout from the portable recording medium in a recording mediumsuch as a hard disc.

When a hard disc is employed as the recording medium intherecording section 11, the processing of reading out thetemplate shape data becomes unnecessary. When the speed of theselection (retrieval) to be described later does not involvea problem, the template data may be read out from thecomputer-readable portable recording medium such as a CD-ROMor a MO each time required.

Therecording section 11 and thereading section 15 maycomprise, for instance, a computer system using a CPU.

As shown in Figure 8, the template data comprises an imagefile in which a plurality of pieces of image data D4 eachrepresenting one template are recorded and a shape file in whicha plurality of pieces of shape data D1 each representing a featureof the shape of a template are recorded in correlation with theimage data D1 for the template. It is preferred that the imagefile includes, in addition to life-size images of the standardtemplates, thumbnail images (scale-down images) of the standardtemplates (e.g., reduced 1/8 by 1/8).

Further, the template data is provided with a table filefor taking a correspondence between each standard template andthe file number of the image file and the shape file for the standard template. Further in order to facilitate, the imagefiles and the shape files are grouped by part, e.g., humerus,knee joint and the like.

As the template shape data D1, vector data representingthe diameter of the bone head, the length of the bone shaft,the length of the bone holder between the bone head and the boneshaft and/ or the angle between the bone shaft and the bone holdercan be employed. With this arrangement, not only the images oftemplates are simply stored in the form of electronic data butalso a database for facilitating retrieval and shape matchingcan be obtained.

Creation of a database on the template data will bedescribed, hereinbelow.

The image file recording means 12 makes an image file inwhich a plurality of sets of template image data D4 obtainedby reading images of a plurality of standard templates with animage scanner or the like, and stores the image file in therecording medium such as a hard disc or a CD-ROM. It is preferredthat thumbnail images of each standard template be included inthe image file in addition to the original image of the standardtemplate as described before. It is further preferred that theimage data be compressed by a known image compression methodsuch as JPEG.

The shape data extracting means 13 measures the contourshape of each standard template by analyzing the image data D4on the template. Then the shapedata extracting means 13 obtains vector data representing the feature of the contour shape ofeach template and inputs the vector data into the shape filerecording means 14 as the template shape data D1. For example,in the case of templates for the femur, sets of data respectivelyrepresenting.the diameter of the bone head, the length of thebone shaft, the angle between the bone shaft and the bone holder,the length of the bone holder, and the like are taken as thevector data.

It is possible to eliminate the shapedata extracting means13. In this case, the operator manually measures the vector dataof each standard template with a scale or the like, and inputsthe data thus obtained into the template data storage means 10through thekeyboard 91.

The shape file recording means 14 makes a table file whichcorrelates the template shape data D1 and the template imagedata D4 with each other while grouping them by part, and recordsthe table file and the shape file thus made on the recordingmedium such as a CR-ROM.

The template data storage means 10 may be variouslymodified.

In one modification of the template data storage means 10,template data of the structure shown in the following table isprepared, and the contour shape of the standard template canbe expressed by generating a curve such as a spline curve onthe basis of control points while referring to information onthe coordinate train of the control points, whether the control points are on an edge, and the like.

data structure of template
1) model number	femur (left), femur (right)
2)size	#	7, #8, #9, #10
3) direction	front , side
4) contour	outer edge, inner edge
5) reference line	centerline, bone head axis
6) reference point	bone head fixing position; 0mm, 5mm, 10mm
7) the others	1: material, weight, price, maker, scale
7) the others	2: notes

With this data structure, when the scale of an image ofa template is varied in order to apply the image of the templateto a displayed image of the bone to be replaced by artificialbone, the edge of the image of the template is smoothly displayedas shown in Figures 9A and 9B, whether the template is suitablefor the bone can be easily checked.

When the degree of suitability is automatically calculated,simple digitization of the image of the template generatesdigitization errors. However, with the method described above,calculation errors can be suppressed.

Preferred embodiments are:

1. An artificial bone template selection systemcomprising

a template data storage means in which template datarepresenting a plurality of templates representing a pluralityof artificial bones of different shapes is stored,

a bone shape measuring means which measures the shape ofbone to be replaced by artificial bone on the basis of bone imagedata representing an image including the bone to be replacedby artificial bone, and

a prospective template selection means which selects, asa prospective template, at least one template the shape of whichsubstantially conforms to the shape of the bone to be replacedby artificial bone as measured by the bone shape measuring meansout of the plurality of templates represented by the templatedata.

2. An artificial bone template selection system asdefined inClaim 1 further comprising

a display means which displays the bone image representingthe shape of the bone to be replaced by the artificial bone andan image of the prospective template(s) selected by theprospective template selection means and

a display control means which causes the display means todisplay the bone image and the image of the prospective templatesuperposed one on another.

3. An artificial bone template selection system as defined inClaim 2 in which an image processing means whichcarries out image processing on at least one of the imagesdisplayed by the display means so that their shapes can be moreclearly discriminated is provided, and
the display control means causes the display means todisplay the image processed by the image processing means inthe processed condition.

4. An artificial bone template selection system asdefined inClaim 1 further comprising an order information outputmeans which outputs information for ordering artificial bonecorresponding to the template selected by the prospectivetemplate selection means.

5. An artificial bone template selection systemcomprising

a bone image display means which displays the bone imagerepresenting the shape of the bone to be replaced by theartificial bone,

a feature point designating means which designates on thebone image displayed by the bone image display means a featurepoint representing the shape of the bone,

a bone shape specifying means which specifies the shapeof the bone on the basis of the feature point designated by thefeature point designating means, and

a prospective template selection means which selects, asa prospective template, at least one template the shape of whichsubstantially conforms to the shape of the bone specified bythe bone shape specifying means out of the plurality of templatesrepresented by the template data.

6. An artificial bone template selection system asdefined inClaim 5 further comprising a display control meanswhich causes the display means to display the bone image andthe image of the prospective template superposed one on another.

7. An artificial bone template selection system asdefined in Claim 6 in which an image processing means whichcarries out image processing on at least one of the imagesdisplayed by the display means so that their shapes can be moreclearly discriminated is provided, and
the display control means causes the display means todisplay the image processed by the image processing means inthe processed condition.

8. An artificial bone template selection system asdefined inClaim 5 further comprising an order information outputmeans which outputs information for ordering artificial bonecorresponding to the template selected by the prospectivetemplate selection means.

9. An artificial bone template display system comprising

a display means which displays an image, and

a display control means which causes the display means todisplay the bone image and an image of at least one of thetemplates stored in the template storage means superposed oneon another.

10. An artificial bone template display system as definedinClaim 9 in which an image processing means which carries outimage processing on at least one of the images displayed by thedisplay means so that their shapes can be more clearlydiscriminated is provided, and
the display control means causes the display means todisplay the image processed by the image processing means inthe processed condition.

11. An artificial bone template display system as definedinClaim 9 further comprising an order information output meanswhich outputs information for ordering artificial bonecorresponding to the template selected by the prospectivetemplate selection means.

12. An artificial bone template storage systemcomprising

an image file recording means which records a pluralityof pieces of template image data, each piece representing animage of one template, in an image file, and

a shape file recording means which records a plurality ofpieces of template shape data representing geometric featuresof each of the templates in a shape file in correlation with the template image data for each template.

13. An artificial bone template storage system as definedinClaim 12 further comprising a shape data extracting meanswhich extracts a plurality of pieces of template shape data,each representing a feature of the shape of a template, on thebasis of template image data on each template.

14. An artificial bone template storage system as definedinClaim 12 in which the shape data is in the form of vectordata.

15. A computer-readable recording medium for storingtemplate data representing a plurality of templates representinga plurality of artificial bones of different shapes in whichare recorded

an image file in which a plurality of pieces of image dataeach representing one artificial bone template are recorded and

a shape file in which a plurality of pieces of shape dataeach representing a feature of the shape of an artificial bonetemplate are recorded in correlation with the image data forthe template.

16. A computer-readable recording medium as defined inClaim 15 in which the shape data is in the form of vector data.